Motor control



' 9 o. E. STAPLES 2,395, 91

MOTOR CONTROL Original Filed Feb. 28, 1941 4 Sheets-Sheet 1 I v l l" I F7621 V INVENIOKI Y I .s E 5774, 455 7 2m mwww awmw ATTORNEY 5 Feb. 26, 1946. Q STAPLES 2,395,591

MOTOR CONTROL Original Filed Feb. 28, 1941 .4 sheets-sheet 2 'INVENTOR.

BY 0n: 5574x 45 ATTORNEY 5 MMZ ZWM MOTOR CONTROL Original Filed Feb. 28. 1941 4 sheets sheet 3 IN VENTOR. E? 574245 A 9 WZ/WBWQWM ATTORNEY5 Feb. 26, 1946. O STAPLES 2,395,591

MOTOR CONTROL Original F iled Feb. 28, 1941 (Sheets-Sheet 4 I I l 1 My 265 r06 r05 INVENTOR.

' i 7 BY 077.5 E. STHPLES H6 4 7pm #WBWW ATTORNEY5 Patented Feb. 26, 1946 MOTOR CONTROL Otis E. Staples, Euclid, Ohio, assignor to The Cleveland Hobbing Machine Company, Cleveland, Ohio, a corporation of Ohio Original application February 28, 1941, Serial No. 381,035. Divided and this application October 2, 1943, Serial No. 504,693

Claims.

The present invention relates to machine tools and the like, and more particularly to a novel variable speed drive for machine tools and the like. This application is a division of my copending application Serial No. 381,035, filed February 28, 1941, now Patent No. 2,362,318, granted November 7, 1944.

The principal object of the present invention is the provision of a novel and improved drive for machine tools and the like comprising a multiple speed electric motor, that is, a motor having a limited number of definite speeds as distinguished from a variable speed electric motor having an infinite number of speeds in combination with means for automatically changing the speed of the motor, and a control device which, when actuated, causes the motor to operate at the same predetermined speed irrespective of the speed at which it was operating when said device was actuated.

Another object of the present invention is the provision of a novel and improved drive for ma chine tools and the like comprising a multiple speed electric motor, that is, a motor having a limited number of definite speeds as distinguished from a variable speed electric motor having an infinite number of speeds, means for automatically changing the speed of the motor, and a control device which, when actuated, causes the motor to operate at the same predetermined speed irrespective of the speed at which it was operating when said device was actuated and including manual means for causing the motor to operate, when started, either in accordance with its predetermined automatic cycle or at a selected one of its speeds.

The present invention resides in certain constructions and combinations and arrangements of parts, and further objects and advantages of the invention will be apparent to those skilled in the art to which the invention relates from the following description of the preferred embodiment thereof described with reference to the accompanying drawings forming a part of the specification and in which:

Fig. 1 is a perspective view of a machine embodying the present invention showing the front and left-hand side of the same as viewed from the front;

Fig. 2 is a perspective view of the machine shown in Fig. 1 showing the front and right-hand in elevation taken approximatel through the center line'of the machine; and

' in the work is rotated about a vertical axis in cutting relation with a disk-like, face-type tool rotated about an axis at right angles to the axis of rotation of the work, while a relative feed movement is efiected between the blank and cutter in a direction longitudinally of the axis of rotation of the work. The cutter has portions of different radii adapted to turn different diameters on the work blank, and the speed of rota-' tion of the work blank is varied as the respective portions of the cutter engage the blank so that the cutting operation is always performed at the maximum cutting speed consistent with other requirements, thereby obtaining maximum production.

Referring to the drawings, the machine shown therein is of the vertical type and comprises a base A which forms a support for a vertical hollow column B which in turn supports a number of machine tool elements including a work head C slidably supported for vertical movement on two pairs of vertically spaced ways I0 and II on the column B, and a tool head D adjustably supported for movement in a horizontal plane in a cylindrical aperture l2 intermediate the ways l0 and II. The work blank W is supported by a suitable chuck l4 fixed to the upper end of a vertical work spindle or machine tool element l5 and a center l6 carried by a suitable tailstock II slidably supported on vertical ways 3 and I9 formedon the side of a work head C. The tailstock I! is adapted to be moved vertically and clamped and unclamped with respect to the ways I8 and I9 by a single operating lever 20.

The tool T which is semi disk-like in shape is carried by a horizontal tool spindle or machine tool element 2| rotatably supported in a tool head D and during the cutting operation is slowly rotated about its axis as the work is fed vertically past the same. In the present instance the tool T is adapted to turn a piece of work having four different diameters, I, 2, 3 and 4, and accordingly the tool has four arcuate cutting portions a, b, c, and d, each of different radius. In order to obtain maximum production from the machine, the work spindle I5 is driven by a multiple speed electric motor 22, see Fig. 3, hereinafter referred to as the cut motor, the speeds of which are so adjusted that maximum cutting speed in feet per minute consistent with other conditions, such as, the character of material being turned, the kind of tool employed, the rate of feed, etc., is maintained irrespective of which portion of the work blank is being turned. As shown, the vertical feed movement of the work head C which effects the feed is produced by a cooperating lead screw 23 and nut 24, the former of which is driven from the work spindle. A high speed reversible electric motor 36, hereinafter referred to as the rapidtraverse motor, operatively connected to the nut 24 provides means for rapidly moving the work head C to bring the work up to the tool at the beginning of the cycle of operations of the machine and for returning the work head to its starting position after the blank has been turned and removed.

The machine is started by pressing a start button El, as will be hereinafter fully described, which closes a circuit to the rapid-traverse mtor 33 causing the same to rotate the nut 24 to move the work head upwardly at a rapid rate. Just prior to the engagement of the work with the tool, an adjustable stop 32 carried on a bar 33 fixed to the top of the work head C actuates a switch 34, stopping the rapid-traverse motor 33 and starting the cut motor 22. Thereafter the work head C continues to move in an upward direction but at a feed rate, and as the different diameters of the work reach cutting position, the speed of the motor 22, which motor has a limited number of definite speeds as distinguished from a variable speed electric motor having an infinite number of speeds, is automatically changed by a plurality of adjustable stops 35, 36, 37, and 38 carried by a plate 39 fixed to the work head C. These stops actuate suitable electric speed selection switches 40, 4|, 42 and 43 fixed to the upper part of the column B and connected in the control circuit in a manner hereinafter described.

After the cutting operation is completed the circuit to the cut motor 22 is opened upon the actuation of a travel limit switch 44 by an ad justable stop 45 on the bar 33, whereupon the machine stops. When the start button 3| is again depressed alter the blank is removed, the rapid-traverse motor operates in the reverse direction to return the work head C to starting position. In order to increase the flexibility of the machine the control for the cut motor 22 preferably comprises a drum controller, designated generally by the reference character E. through the medium of which control circuits for the motor can be so selected that the motor will go through its cycle of various speeds automatically or any one of its various speeds can be selected. In the latter event the selected speed alone will operate during the entire cutting operation. In addition to the automatic position, designated auto, and the four different speed positions, designated 1, 2, 3, and 4, the drum controller E also has an off position, designated off.

The work spindle i5 is rotatably supported by anti-friction bearings in the work head C and is driven from the cut motor 22 which is located within the column B but is fixed to and carried by the work head C through the medium of a bracket 48. The armature shaft 41 of the motor 22 is connected to a short shaft 48 by a coupling 49 of conventional construction. The shaft 48 is rotatably supported in the work head C and has a small gear 58 fixed thereon which is continuously in mesh with a large gear 5| fixed to a shaft 52 also rotatably supported in the work head C and which projects into a gear compart ment 53 in the lower front part of the work head C. The shaft 52 is operativcly connected to a short shaft 54 through the medium of gears 55 and 58 located within the gear compartment and fixed to the shafts 52 and 54, respectively. The shaft 54 is rotatably supported in the work head C and is provided at the left-hand end, as viewed in 3, with a bevel gear 51 continuously in mesh with the bevel gear 58 fixed to the work spindle [5. The gear compartment 53 is adapted to be closed by a removable cover 59, and the gears therein are preferably operated in oil.

The lead screw 23 is rotatably supported m the work head C against axial movement relative thereto and is rotated at a relatively slow speed and in timed relation to the rotation of the work spindle IE to effect the feed movement of the work head C by the cut motor 22 to which it is operatively connected by a worm wheel 60 fixed to its upper end, which worm wheel is continuously in mesh with a worm (not shown) keyed on a horizontal shaft (not shown) rotatably supported in the work head C. This shaft, like the shaft 52, projects through the partition 63 in the work head C and the left-hand end thereof, is provided with a gear (not shown) in mesh with a gear 65 fixed to the shaft 54 to the left of the gear 55.

As previously stated, the nut 24 with which the lead screw 23 cooperates is adapted to be rotated at a high rate of speed to produce a rapidtraverse movement of the work head C in either direction by the rapid-traverse motor 30 which is supported on the bed A within the column B. The armature shaft 66 of the motor 30 is connected by a coupler 61 to a short shaft 68 rotatably supported in a bracket 69 which supports the nut 24. The shaft 68 is provided with a worm, not shown, continuously in mesh with a worm wheel H formed about the circumference of the nut 24. The lead screw 23 is pref erably provided with a telescopic guard, designated generally as 12, which prevents the entrance of chips, etc, into the interior of the bracket 69.

As the work head C moves vertically the tool spindle 2i, and, in turn, the tool or cutter T are rotated slowly at varying rates of speed depending upon the radius of the particular cutting edge of the tool in contact with the work blank at any time, etc. As shown, the rotation of the tool is effected by a cam plate bolted or otherwise suitably detachably connected to the work head C, which cam plate has a cam slot 85 formed therein and within which a cam roller 81 engages. The cam roller 81 is adjustably fixed to a rack bar 88 slidably supported in an extension of the tool head D. The rack teeth 90 of the rack bar 88 are continuously in mesh with a gear fixed to the lower end of the tool spindle 2!, as viewed in Fig. '7. In order to eliminate back-lash in the mechanism operatively connecting the tool spindle 2| to the cam plate 85, the tool spindle is continuously urged in a clockwise direction, as viewed in Fig. 2 by an air motor (not shown) located within the column B, the piston rod l0! of which motor connected by a sprocket chain (not shown) to a sprocket wheel (not shown) fixed to the tool spindle 2|. The air motor is continuously supplied with air under pressure during the operation of the machine.

The cut motor 22 shown is of the four-speed alternating current type which allows the spindle to be rotated at any of four different speeds, thus producing a machine which will accommodate the turning of pieces of work having four or less different diameters thereon with the cutting operation always being performed at maximum efficiency. It is to be understood, however, that a motor having any desired number of speeds can be employed. The type of motor selected will depend upon the particular article to be turned. A four-speed motor is selected in the present instance because four speeds are suflicient to accommodate most articles which the machine shown is designed to turn. In the event that it is desired to turn an article having more than four different diameters on the machine shown, two of the diameters which most nearly approach each other in size can be turned at the same speed or the shortest diameter can be turned at one of the four speeds which is most appropriate.

The relative positions of the various parts of the machine at the commencement of a cycle of operations is shown in Fig. 1. As shown in this figure the Work head is at the bottom of its travel and a work blank has been positioned in the work head. The machine is started by depressing the start push button switch 3I located on a control panel I 04 fixed to the left-hand side of the machine in a position readily accessible to the operator. With the drum controller E set at auto, the depressing of the start push button switch 3I closes a circuit from line LI through normally closed stop push button switch I05, line I06, normally open start push button switch 3|,

line I01, operating solenoid I08 of relay I09, line H0, contacts III of a travel limit switch 44, line H2, overload contacts 96, line 91, overload contacts 98, line 99, overload contacts H3, line H4, overload contacts I I5, line H6, overload contacts H1, line I I8, overload contacts I I9, to L3. The overload contacts 96, 95, H3, H5, H1 and H9 are located on motor control panels, hereinafter referred to. The particular motor control panel upon which these overload contacts are positioned is shown in the wiring drawing.

Energization of the operating solenoid I08 of relay I09 closes the normally open contacts I20, I2I and I22 thereof and opens the normally closed contacts I23 thereof. The closing of the contacts I of relay I09 establishes a circuit from the line LI through the normally closed stop push button switch I05, line I06, contacts I20, line I24, operating solenoid I25 of rapid-traverse motor control panel I26, line I21, closed contacts I28 of change-over switch 34, line H0, closed contacts I I I of travel limit switch 44, line I I2, etc., to L3. Energization of operating solenoid I25 of rapidtraverse motor control panel I26 closes the nor mally open contacts I 30, I3I and I32, connecting the rapid-traverse motor 30 to the power lines LI, L-2 and L--3 in such a manner that the motor is operated in a direction to rapidly raise the work head C.

Simultaneously with the closing of contacts I30, I3I and I32 of the rapid-traverse motor control panel I26, normally open contacts I33 on the same panel are closed. These contacts are in parallel circuit with the contacts I20 of relay I09 and establish a holding circuit for the operating solenoid I25 continuing the operation of the rapid-traverse motor 30 after the start push button switch 3| is released. The closing of the contacts I2I of relay I09 establishes a circuit from the line L'I through the stop push button switch I05, line I06, contact bar I35 of drum controller E, line I36, contacts I2I, line I 31, operating solenoid I38 of relay I39, line I I0, closed contacts III of travel limit swtich 44, line H2, etc., to L3. Energization of the operating solenoid I38 of relay I39 closes the normally open contacts I40 and MI thereof. The contacts I49 are in parallel circuit with the contacts I2I of relay I09 and the closing of these contacts establishes a holding circuit for the operating solenoid I38 of relay I39 maintaining the solenoid energized after the start push button switch 3| is released. The closing of contacts I22 of relay I09 and the closing of contacts I4I of relay I39 do not establish circuits since these contacts are in series with open contacts I42 of change-over switch 34.

Just prior to the engagement of the work with the tool, the stop 32 actuates the change-over switch 34 to open the closed contacts I20 thereof and close the open contacts I42. The opening of contacts I28 of change-over switch 34 deenergizes the operating solenoid I25 of rapid-traverse motor control panel I26 disconnecting the rapidtraverse motor from the line and allowing the same to stop. The closing of contacts I42 establishes a circuit from the line L-I through the stop push button switch I05, line I96, normally open contacts I M of relay I39, which are now closed, line I43, contact bar I44 of drum controller E, line I45, operating solenoid I46 of relay I 41, line I 49, closed contacts I42 of change-over switch 34, line H9, closed contacts III of travel limit switch 44, line H2, etc., to L3.

Energization of the operating solenoid I46 of the relay I41 closes the normally open contacts I56, I5I and I52 thereof. This establishes a circuit from the line L--I through the stop push button switch I05, wire I06, closed contacts I4I, line I43, contact bar I44, line I53, normally closed contacts I54 of speed selection switch 42 which also includes normally open contacts I56, line I51, contacts I50, line I58, normally closed contacts I59 of speed selection switch 43 also having normally open contacts I62, line I63, contacts I5I, line I64, contacts I52, line I65, normally open contacts I66 of speed selection switch 40, which contacts by prearrangement are now closed by the stop 35 on the plate 39, line I01, operating solenoid I09 of relay I09, line H0, closed contacts III of travel limit switch 44, line I I2, etc., to L3. This circuit again closes the normally open contacts of relay I09, contacts I22 of which establish a circuit from the line I31, closed contacts I22 of relay I09, line I61, operating solenoid I68 of motor control panel I69, line I10, normally closed contacts "I of relay I12, line I49, closed contacts I42 of change-over switch 34, line H0, closed contacts III of travel limit switch 44, line H2, etc., to L3.

Energization of'the operating solenoid I69 of motor control panel I69 closes the normally open contacts I13, I 14, I 15 and I 16 thereof, connecting-the motor 22 to the power lines Ll, L2 and L-3 in such a manner that the motor rotates at one of its four speeds, which speed is hereinafter referred to as the first speed. Simultaneously with the closing of contacts I13, I14, I15 and I16 of motor control panel I69, normally open contacts I11 are also closed. These contacts establish a holding circuit for the operating solenoid I68 of the motor control panel I69 after the speed selection switch 43 is opened upon movement of the stop 35 away from the operating arm thereof. This holding circuit is from the line L-I through stop push button switch I05, line I03, closed contacts I4I of relay I39, line I43, contact bar I44 of drum controller E, line I53, normally closed contacts I54 of speed selection switch 42, line I51, closed contacts I50 of relay I41, line I58, normally closed contacts I59 of speed selection switch 43, line I63, contacts I5I, line I64, contacts I52, line I65, contacts I11, line I91, operating solenoid I80, line I10, normally closed contacts I1I, line I49, closed contacts I42, line H8, closed contacts III, line II2, etc., to L3.

The operating solenoid I18 of relay I19 is in parallel circuit with the operating solenoid I68 of motor control panel I99 and the relay is actuated simultaneously with, the contacts of the motor control panel I89 to open the normally closed contacts I80 thereof. The contacts I80 of relay I19 are in series circuit with the operating solenoids of the motor control panels, hereinafter referred to, which cause the motor 22 to operate at its third speed and the opening of these contacts makes certain that these operating solenoids will not be simultaneously energized with the operating solenoid I68 of motor control panel I99 which causes the motor to operate at its first speed.

The machine continues to operate with the cut motor rotating at its first speed until the stop 36 closes the contacts I8! of the speed selection switch 4 I, whereupon a circuit is established from the line LI through the stop push button switch I05, line I06, closed contacts I4I of relay I39, line I43, contact her I44 of drum controller E, line I53, normally closed contacts I54 of speed selection switch 42, line I51, closed contacts I56 of relay I41, line I58, normally closed contacts I59 of speed selection switch 43, line I63, closed contacts I5! of relay I41, line I64, normally open contacts I8I of speed selection switch 4I, line I82, operating solenoid I83 of relay I12, line I84, normally closed contact I23 of relay I09 which is now de-energized, line I49, closed contacts I42 of change-over switch 34, line I I0, closed contacts III of travel limit switch 44, line II2, etc., to L-3. Energization of the operating solenoid I83 of relay I12 opens the normally closed contacts I1! and I85 and closes the normally open contacts I89 thereof. The opening of the normally closed contacts I1! of relay I12 opens the circuit through the operating solenoid I68 of motor control panel disconnecting the connections to the motor 22 by virtue of which it operates at its first speed. This also deenergizes the operating solenoid I19 of relay 119 allowing the contacts I80 thereof to close.

The closing of the contacts I89 of relay I12 establishes a circuit through the operating solenoid I81 of motor control panel I88 from the line LI, through stop push button switch I05, line I95, closed contacts I4! of relay I39, line I43, contact bar 244 of drum controller E, line I53, normally closed. contacts I54 of speed selection switch, 42, line I51, closed contacts I50 of relay I-41, line I58, normally closed contacts I59 of speed selection switch 43, line I53, closed contacts I5I of relay I41, line I84, contacts I86, line I89, operating solenoid I81, line 584, normally closed contacts I23 of relay I09, line I49, closed contact I42 of change-over switch 34, line IIO, closed contacts I II of travel limit switch 44, line II2', etc., to L-E. Energization of the operating solenoid I81 of the motor control panel I88 closes the normally open contacts I90, I9I, I92 and I93 to the power lines in such a manner that the motor continues to operate but at a different speed, herein referred to as the second speed. Simultaneously with the closing of the contacts I90, I9I, I92 and I93 of motor control panel I88, contacts I94 of the same motor control panel are closed. These contacts are in parallel circuit with the contacts I86 of relay I12 and establish a holding circuit therearound which maintains the operating solenoid I81 of motor control panel I88 energized after the contacts I8I of speed selection switch 4| have opened by the stop 36 moving clear of the actuating arm of said switch. Operating solenoid I95 of relay I98 is in parallel circuit with the operating solenoid I81 of motor control panel I88 and is energized simultaneously therewith to open the normally closed contacts I91 of said relay, which contacts are in series circuit with the operating solenoid I98 of motor control panel I99 by virtue of which the motor is connected to the line LI, L-2, and L--3 in such a manner that it operates at a difierent speed, hereinafter referred to as its fourth speed, thus eliminating any possibility of the operating solenoid I98 being simultaneously energized with the operating solenoid I81.

The machine continues to operate with the motor 22 rotating at its second speed until the speed selection switch 42 is actuated by engagement of the stop 31 with the operating arm thereoi Actuation of this switch by the stop 31 opens the normally closed contacts I54 and closes the normally open contacts I58 thereof. The opening of the normally closed contacts I54 of speed selection switch 42 breaks the circuit to the operating solenoid I81 of motor control panel I88, deenergizing the circuits by virtue of which the motor operates at its second speed. The operating solenoid I95 of relay I96 which is in parallel circuit with the operating solenoid I81 of motor control panel I88 is deenergized at the same time, allowing the normally closed contacts I91 of said relay to close. The closing of contacts I58 of speed selection switch 42 establishes a circuit from the line L-I, through the stop push button switch I05, line I08, contacts I4I of relay 539, line I43, contact bar I44 of drum controller E, line I53, contacts I56 of speed selection switch 42, line 200, normally closed contacts 20I of motor control panel I88, line 202, normally closed contacts of relay I19, line 203 normally closed contacts 204 of motor control panel I99, line 285, operating solenoid 2 I 0 of motor control panel 2H, line 2I2, normall closed contacts I of relay I12, line I84, normally closed contacts I23 of relay I09, line I49, closed contacts I42 of change-over switch 84, line IIO, closed contacts III of travel limit switch 44, line II2, etc., to l 3. The contacts 20I of motor control panel I88, which are now closed, were opened while the motor was operating at its second speed, thus preventing an possibility of the operating solenoid 210 of motor control panel 2II being energized simultaneousl with the energization of the operating solenoid I81 of the motor control panel l88 by virtue of which the motor is caused to operate at its second speed. In like manner the contacts 204, which are now closed, will be open when the motor is operating at its "fourth" speed, thus preventing simultaneous energization of the operating solenoid 2I0 of motor control panel 2II with the operating solenoid I98 of motor control panel I99.

Energization of the operating solenoid 2I0 of motor control panel 2I I closes the. normally open contacts 2I5, 2I6, 2I1, 2I8 and 2I9 thereof. The closing of the normally open contacts 2 I8 establishes a circuit from the line 205 through the contacts 2H3, line 220, operating solenoid 22I of motor control panel 222 to line 2 I 2. As previously stated, energization of the operating solenoid 2 I of motor control panel 2 closes the normally open cont-acts 2I5, H6, and 2I1 thereof and the energization of the operating solenoid 22I of the motor control panel 222 closes the normall open contacts 223, 224 and 225 thereof. The closing of the contacts 2I5, 2I6, 2I1, 223, 224 and 225 connects the motor 22 to the source of power in such a manner that the motor operates at a different speed than heretofore, which speed is herein referred to as the third speed. The closing of normally open contacts 2I9 of motor control panel 2II establishes a holding circuit around the contacts I56 of speed selection switch 42 This maintains the operating solenoids 2I0 and 225 of the motor control panel 2H and 222, respectively, energized after the contacts I56 have opened upon movement of the stop 31 away from the actuating mechanism of the speed selection switch 42.

The machine continues to operate with the motor rotating at its third" speed until the speed selection switch 43 is actuated by engagement of the stop 32 with the operating arm thereon.

Actuation of this switch by the stop 38 opens the normally closed contacts I59 and closes the normally open contacts I62 thereof. The closing of the normally open contacts I62 of speed selection switch 43 establishes a circuit from the line LI through the stop push button switch I05, line .3

I05, contacts I4I of relay I39, line I43, contact bar I44 of drum controller E, line I53, contacts I54 of speed selection switch 42, line I51, contacts I50 of relay I41, line I58, contacts I62 of speed selection switch 43, line 230, normally closed contacts 23I of motor control panel I69, line 232, normally closed contacts I91 of relay I96, line 229, operating solenoid I98 of motor control panel I99, line 2 I2, normally closed contacts I of relay I12, line I84, normally closed contacts I23 of rela I09, line I49, contacts I42 of change-over switch 34, line IIO, contacts III of travel limit switch 44, line I I2, etc., to L3.

Energization of the operating solenoid I98 of motor control panel I99 closes the normally open contacts 233, 234, 235 and 236, and opens the normally closed contacts 204 thereof, The closingof the normally open contacts 236 establishes a circuit for the operating solenoid 240 of motor control panel 24I from the line 230, through line line 232, etc, closing the normally open contacts 242, 243, 244 and 245. The closing of contacts 233, 234, and 235 of motor control panel I99 and contacts 242, 243, and 244 of motor control panel 24I connects the cut motor 22 to the lines L-i, L-2 and L3 in such a manner that the motor operates at a different speed, herein referred to as the "fourth speed. The closing of the normally open contacts 245 of motor con- .trol panel 24I, which are in parallel circuit with the normally open contacts I62 of speed selection switch 43, maintains closed the circuit to the operating solenoids I 98 and 240 of the motor control panels I 99 and MI after the contacts I62 open due to the stop 30 moving away therefrom. The contacts I59 of speed selection switch 43 are in series circuit with the operating solenoid I81 which when energized causes the motor 22 to operate at its second speed and the opening of these contacts prevents energization of the operating solenoid I81 simultaneous with the energization of the operating solenoids I98 and 240 of the motor control panels I99 and HI.

Any possibility of the operating solenoid I68 of the motor control panel I69 or the solenoids 2H] and 22I of the motor control panels 2H and 222, respectively, being energized simultaneously with the energization of the operating solenoids I98 and 240 of motor control panels I99 and 24I, respectively, is prevented in the manner previously pointed out.

The cut motor 22 continues to operate at its fourth speed until the travel limit switch 44 is actuated by the stop 45 to open the normally closed contacts III thereof and close the normally open contacts 246. The opening of the normally closed contacts III of the travel limit switch 44 breaks the circuit to the operating solenoids I96 and 240 of the motor control panels I99 and 24I, respectively, whereupon the motor comes to rest. If at any time during the operation of the motor 22 at any of its speeds other than the first speed the start button 3| is depressed, the motor will drop back to its first" speed by virtue of the closing of contacts I22 of relay I09 and the opening of contacts I23 of the same relay. The closing of contacts I22 completes the circuit to the necessary relays, etc., to connect the cutmotor 22 to the lines L-I, L4 and L3 in such a manner that itoperates at its first speed, and the simultaneous opening of the normally closed contacts I23 breaks the circuit to all other relays, etc., as will be apparent from the wiring diagram. The cut motor 22 then continues to operate at its first speed until one of the speed selection switches 4|, 42 and 43 is actuated by its respective stop, whereupon the motor operates at the selected speed and continues its automatic cycle of operation. Any possibility of energizing the operating solenoids I98, 240, 2I0 and 22I of the motor control panels I99, 24I, 2H and 222, respectively, simultaneously with the operating solenoid I81 of motor control panel I88 is prevented by the normally closed contacts I35 of relay I12, which contacts open along with the closing of contacts I86 which latter contacts energize the operating solenoid I81.

With the work head C at the upper limit of its travel, the work blank is removed and thereafter the work head is returned to its initial Position by again depressing the start push button 3!. When the start push button switch 3| is now depressed, a circuit is established from the line LI through the stop push button switch I05, line I06, start push button switch 3I, line 241,

operating solenoid 240 of motor control panel I26,

line 250, contacts 246 of travel limit switch 44, line II2, etc., to L3. Energization of the operating solenoid 248 of 'motor control panel I26 closes the normally open contacts 25I, 252, 253 and 254 thereof. The closing of contacts 25I, 252 and 253 connects the rapid-traverse motor 30 to the lines LI, L2 and L3 in such a manner that it rotates in the opposite direction, that is, in a direction to lower the work head 0. The

closing of the normally open contacts 254 of the motor control panel I26 which are in parallel circuit with the start push button switch 3I maintains the circuit to the operating solenoid 248 after the start push button switch has been released. As the work head C moves down, the change-over switch 34 is reset by the stop 32 to again close the contacts I28 and open the contacts I42 thereof. The spindle head continues to move down at a rapid-traverse rate until the travel limit switch 44 is actuated by the stop 32 to open the closed contacts 246 and close the open contacts III thereof. The opening of the contacts 246 breaks the circuit to the operating solenoid 248 of motor control panel I26, stopping the rapid-traverse movement. The electrical circuits have now all been returned to their original positions and the cycle of operations can again be completed by depressing the start push button switch 3 I.

As previously stated, the drum controller E has positions to which it can be turned, designated first, second, third and fourth, corresponding with the respective speeds of the cut motor, and when turned to either of these positions the cut motor 22 will operate at the speed selected throughout the entire cutting operation. In all of the above-mentioned four positions, the

line I96 is connected to the line I36 by the contact bar 255, thus establishing the same circuits as are established by the contact bar I35 when the drum controller E is set at auto. When the drum controller E is in first position, the line I43 is connected to the line I61 through the contact bar 256. This establishes a circuit from the line L-I through the stop push button switch I 65, line I95, contacts I4I of relay I39, line I43, contact bar 256, line I61, operating solenoid I68 of motor control panel I66, line I19, contacts I1I of relay I12, line I49, contacts I42 of change-over switch 34, line IIO, contacts II I of travel limit switch 44, line I|2, etc., to L3, upon the closing of the contacts I42 of change over switch 34 which takes place, as previously explained, just prior to the engagement of the work with the cutter. This circuit is maintained throughout the upward continued movement of the work head C as the selection switches for the other speeds are not connected in this circuit.

The fact that various selection switches are subsequently actuated has no effect upon the circuit since the circuits for energizing the operating solenoids of other motor control panels are open as long as the operating solenoid of the motor control panel I59 is energized, as previously explained.

When the drum controller E is turned to second position, the contact bar 255 is connected to line I89 in place of line I51. This establishes nected to line 239 causing the operating solenoids of motor control panels 2H and 222, and I99 and 24I, respectively, upon the closing of contacts I42 of change-over switch 34, causing the cut motor 22 to operate at its third or fourth speed, as the case may be, in a manner similar to that in which it was caused to actuate at its first and second speeds when the contact bar 256 is connected to the lines IE1 and I89, respectively.

Coolant for the tool is adapted to be supplied by a pump, not shown on the drawings, which pump is driven by an electric motor 251, the operation of which is controlled by a motor control panel 258, the operating solenoid 259 of which is connected in the control circuit previously described in such a manner that the motor 251 operates only while the cut motor 22 is operated. When the operating solenoid 259 of the motor control panel 259 is energized, the normally open contacts 260, 25I and 262 thereof are closed connecting the motor to the lines L-I, L2 and L3 causing the same to operate. A snap switch 263 located on the control panel I04 provides means for preventing operation of the motor 251 when it is desired to operate the cut motor 22 without the coolant motor 251. When the switch 263 is closed, a circuit is established from the line I31 through the switch 263, line 265, operating solenoid 259 of motor control panel 258 to line I49. This circuit is in parallel with the operating solenoid I38 of relay I39 when the contacts I42 of change-over switch 34 are closed.

The cut motor 22 is a four-speed alternating current motor of conventional construction. The connections between the motor control panels which actuate the same and the motor are not referred to herein in detail but are well-known in the art and are shown on the wiring diagram. In the wiring diagram, the leads to the motor 22 are designated by the reference characters TI to T--I4, inclusive. The leads to the motor 39 are designated by the reference characters T--I5, T-I6 and TI1 and the leads to the motor 251 by the reference characters TI8, T-I9 and T28. The machine can be stopped at any time by depressing the stop push button switch I95. In the embodiment of the invention shown, only two adjustable stops 32 and 45 are employed on the bar 33. In this event the stop 32 performs the dual function of determining the change-over position, that is the position where the rapid-traverse up movement of the work head C stops and the feed movement starts in the cycle of operations, and the down position of the work head C. In other words, the stop 33 actuates the change-over switch 34 and the travel limit switch 44, the latter when the work head C is moving in a downward direction. Alternately a separate adjustable stop may be used to actuate the change-over switch 34, in which event the sole function of the stop 32 shown would be that of limiting the downward movement of the work head C.

From the foregoing description of the preferred embodiment of the invention it will be apparent that the objects of the invention heretofore enumerated and others have been accomplished and that there has been provided a new and improved drive for machines of the character described etc. While the preferred embodiment 1 of the invention has been described with considerable detail, it will be apparent that the invention is not limited to the particular construction shown, for example, a motor having any number of different speeds may be controlled. It will also be apparent that the motor can be operated at its various speeds in any desired sequence by suitably arranging the stops which actuate the speed selecting switches. Other alternative constructions will be apparent to those skilled in the art to which the Invention relates and it is my intention to hereby cover all adaptations, modifications and uses thereof which comes within the practice of those skilled in the art to which the invention relates.

The phrase multiple speed electric motor" as used throughout this specification and the following claims, defines an electric motor having a limited number of definite speeds as distinguished from a variable speed electric motor having an infinite number of speeds.

Having thus described my invention, I claim:

1. In a device of the character referred to, the combination of: a frame; a member movably supported by said frame; means comprising a multiple speed alternating current electric motor for moving said member; and means for causing said motor to automatically operate in sequence at a plurality of speeds whereby said member performs a cycle of operations, said means including control mechanism which when actuated at any time subsequent to the initiation of said cycle of operations and prior to the completion thereof causes said motor to operate at a predetermined speed which speed is always the same regardless of the place in the cycle of operations at which said control mechanism is actuated and continue at said speed until the next speed change in the cycle of operations is reached after which the normal cycle of operations i continued.

2. In a device of the character referred to, the combination of a frame; a member movably supported by said frame; means comprising a multiple speed alternating current electric motor for moving said member; and means for causing said motor to automatically operate in sequence at a plurality of speeds whereby said member performs a cycle of operations, said means including a manually operable control device which when actuated prior to the initiation of said cycle of operations initiates the same and which when actuated at any time subsequent to the initiation of said cycle of operations and prior to the completion thereof causes said motor to operate at a predetermined speed which speed is always the same regardless of the place in the cycle of operations at which said control device is actuated and continue at said speed until the next speed change in the cycle of operations is reached at which time the normal cycle of operations is resumed.

3. In a device of the character referred to, the combination of a frame; a member movably supported by said frame; means comprising a multiple speed alternating current electric motor for moving said member; and means actuated in timed relation to the movement of said member for causing said motor to automatically operate in sequence at a plurality of speeds corresponding with predetermined movements of said member whereby a cycle of operations is performed, said means including a control device which when; actuated prior to the initiation of said cycle of operations initiates the same and which when actuated at any time subsequent to the initiation of said cycle of operations and prior to the completion thereof causes said motor to operate at a predetermined speed which speed is always the same regardless of the place in the cycle of operations at which said control device is actuated and continue at said speed until the next speed change in the cycle of operations is reached after which the normal cycle of operations is completed.

4. In a device of the character referred to, the combination: a frame; a member movably supported by said frame; means comprising a multiple speed alternating current electric motor for moving said member; and means including selector mechanism for causing said motor to operate at a selected one of a plurality of its speeds or to automatically operate in sequence at a plurality of speeds whereby said member performs a cycle of operations, said means including control mechanism which when actuated at any time subsequent to the initiation of said cycle of operations and prior to the completion thereof causes said motor to operate at a predetermined speed which speed is always the same regardless of the place in the cycle of operations at which said control mechanism is actuated and continue at said speed until the next speed change in the cycle of operations is reached at which time the normal cycle of operations is resumed.

5. In a device of the character referred to, the combination of: a frame; a member movably supported by said frame; means comprising a multiple speed alternating current electric motor for moving said member; and means including selector mechanism for causing said motor to operate at a selected one of a plurality of its speeds or to automatically operate in sequence at a plurality of speeds whereby said member performs a cycle of operations, said means in cluding a manually operable control device which when actuated with said motor at rest initiates actuation thereof and which when actuated subsequent to the initiation of said cycle of operations and prior to the completion thereof always causes said motor to operate at a predetermined speed which speed is always the same regardless of the place in the cycle of operations at which said control device is actuated and continue at said speed until the next speed change in the cycle of operations is reached after which the normal cycle of operations is continued.

OTIS E. STAPLES. 

